Multipurpose boot

ABSTRACT

Footwear comprising a foot-fitting portion with a rear portion ( 1   a ), a base ( 2 ) fitted under the rear portion of the foot-fitting portion, a heel ( 3 ) that is releasably fastened to the base ( 2 ) by close-fitting assembly means ( 4, 16, 2   a,    3   a ), and means ( 5, 7, 17 ) for automatic locking and manual unlocking of said assembly means, wherein the base ( 2 ) is a thin plate of plastics material having at least three tapped metal inserts (nuts) ( 11, 12 ) for receiving three fastener screws ( 14, 15 ) for fastening the base ( 2 ) under the rear portion ( 1   a ) of the foot-fitting portion of the footwear.

The present invention relates to the field of footwear. More precisely,footwear of the invention possesses means for receiving either aplurality of interchangeable heels, or else a member for rehabilitationpurposes.

BACKGROUND OF THE INVENTION

In the field of footwear, there exists a demand to be able to change theappearance of a piece of footwear, in particular women's footwear, withthe possibility of changing the shape or the material or the color ofthe heel of the footwear while retaining the same foot-fitting portion.Furthermore, certain kinds of footwear may constitute instruments fortraining or rehabilitation by providing the user's heel with differentkinds of bearing on the ground, depending on whether it is necessary towork on balance, ankle strength, bearing of the foot on the ground, . .. .

Proposals have already been made for many years for a removable heel toprovide an interchangeability option, but without that culminating in acommercially satisfactory solution. The means that makeinterchangeability possible have always been complicated, andimplementing them often requires recourse to tooling that the user doesnot master thoroughly. When the heel can be assembled and removed byhand, the quality of the connection is not sufficient to ensure that thefootwear can be used safely. Finally, under other circumstances, thematerials used do not present sufficient strength to enable prolongeduse of the footwear.

Those known means are also unsatisfactory concerning footwear that has atechnical function and that is stressed in a manner that is even moresevere than ordinary footwear.

The present invention seeks to satisfy appropriately the need for aninterchangeable heel by providing a structure for the heel and thefootwear that receives it that is suitable for withstanding the highforces to which the heel is subjected while the footwear is being worn.

SUMMARY OF THE INVENTION

The present invention provides footwear comprising a foot-fittingportion with a rear portion, a base fitted under the rear portion of thefoot-fitting portion, a rear bearing member of the footwear for bearingon the ground that is releasably fastened to the base by close-fittingassembly means, and means for automatic locking and manual unlocking ofsaid assembly means, the footwear being characterized in that the baseis a thin plate of plastics material having at least three tapped metalinserts (nuts) for receiving three fastener screws for fastening thebase under the rear portion of the foot-fitting portion of the footwear.

It has been found during thorough testing of the strength of suchfootwear that breakage occurs at the location where the base is fastenedto the foot-fitting portion. The prior art proposes ordinary fasteningby means of through screws that are found not to be strong enough, giventhe small thickness of the base that receives them. This small thicknessis required for reasons of the appearance of the footwear so that thereis no too-visible discontinuity between the heel and the footwear.

In preferred manner, the inserts are as far apart from one another aspossible and they are received in regions of extra thickness of thebase, outside the assembly means.

The heel includes recesses for housing said regions of extra thicknesson being assembled with the base.

The assembly means are constituted by a male dovetail projecting fromthe base and a female dovetail formed in the heel. The regions of extrathickness having the nuts embedded therein are located outside the maledovetail, and the heel includes corresponding recesses for receivingthese regions of extra thickness during mutual engagement and assemblyof the two dovetails. The visible peripheral portion of the base canthus continue to be fine.

Other characteristics and advantages of the invention appear from thedescription given below of an embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWING

Reference is made to the accompanying drawing, in which:

FIG. 1 is a perspective view from beneath of the rear portion of a pieceof footwear of the invention; and

FIG. 2 is a section view on plane II-II of FIG. 1, with the heel and thebase assembled together.

DETAILED DESCRIPTION OF THE INVENTION

In the figures, the piece of footwear of the invention comprises afoot-fitting portion 1 with the rear portion 1 a thereof being shown. Atits bottom, this foot-fitting portion comprises, in known manner: aninsole; a welt; a filler having a shank mounted thereon; and a sole.

A base 2 is fitted on the bottom and is used as a removable assemblypart for a heel 3. At its periphery, the base is a thin plate ofsynthetic material (e.g. thermoplastic material) and along itslongitudinal axis XX, corresponding to the long direction of thefootwear, it possesses a tenon 4 in the form of a male dovetailprojecting from the free surface 2 a of the thin plate. In the center ofthe tenon, a resilient tongue 5 integrally molded with the tenon issuitable for being resiliently retracted into a housing 6 in the tenonby pushing one end 5 a of the tongue down towards the sole, which end 5a projects beyond the tenon towards the toe of the footwear. In its restposition, the visible surface 5 b of the tongue 5 lies in the same planeas the visible surface 4 a of the dovetail 4. This surface carries astud 7, which thus projects from the plane when the tongue is at restand which is retracted beneath the plane when the tongue 5 is pusheddown into the housing 6 by acting on the pusher 5 a.

Outside the tenon 4, the thin plate includes regions of extra thickness8, 9, and 10, the first two being situated at the front of the base(front relative to the front of the footwear), on either side of thetenon 4, while the third is situated at the back of the tenon, on theaxis thereof.

Each region of extra thickness constitutes a block overmolded on a metalinsert 11, 12, or 13 that is constituted by a nut and that is suitablefor receiving a screw such as the screws 14 and 15 in FIG. 2.

The heel 3 of the footwear possesses assembly means complementary tothose of the base 2. They are constituted by a female dovetail 16, by arecess 17 formed in the base of the dovetail 16, and by recesses 18, 19,and 20 situated outside the female dovetail 16, in a relative layoutidentical to that of the regions of extra thickness and the tenon of thebase 2.

The base is fitted to the foot-fitting portion of the footwear by meansof screws 14 and 15 passing through the bottom of the rear portion 1 aof the footwear, as shown in FIG. 2. This fastening is particularlystable since the three nuts 11, 12, and 13 are spaced apart from oneanother. The base is fastened permanently to the footwear. The heel isthen slid onto the base along arrow F in FIG. 1. The dovetails engageone in the other until the stud 7 comes into contact with the front edgeof the heel. The stud advantageously possesses a slope that serves toavoid blocking the engagement movement, so the movement continues bycausing the tongue 5 to be deflected into the inside of the housing 6.At the end of engagement, the stud 7 is received in the recess 17 of theheel by the resilient return of the tongue to its rest position. Theheel is then locked on the base. The fastening is a tight-fit because ofcompression stress that exists on the heel between the sloping flanks ofthe female dovetail and the top surface 3 a of the heel, with thedimensions thereof and the dimensions of the base being arranged toensure that this assembly prestress occurs. The regions of extrathickness are of dimensions that are smaller than the dimensions of thehousings that receive them so that there is no interference between themand the active assembly means.

The above description relates to a town shoe, but the invention is notlimited to that kind of shoe. The invention also applies to footwear forperforming technical functions such as orthopedic footwear or footwearfor sports or medical use. The foot-fitting portion of such footwear isadapted to holding the foot to the function or the exercise for whichthe footwear is intended, while the rear portion of the foot-fittingportion, fitted with the base as described above, can be fitted with amember that is adapted to the nature of the support that it is desiredto obtain (point support by means of a sphere, off-centered support, . .. ).

1. Footwear (1) comprising a foot-fitting portion with a rear portion (1a), a base (2) fitted under the rear portion of the foot-fittingportion, a rear bearing member (3) of the footwear for bearing on theground that is releasably fastened to the base (2) by close-fittingassembly means (4, 16, 2 a, 3 a), and means (5, 5 a, 7, 17) forautomatic locking and manual unlocking of said assembly means, whereinthe base (2) is a thin plate of plastics material having at least threetapped metal inserts (nuts) (11, 12, 13) for receiving three fastenerscrews (14, 15) for fastening the base (2) under the rear portion (1 a)of the foot-fitting portion of the footwear.
 2. Footwear according toclaim 1, wherein the inserts (11, 12, 13) are as far apart from oneanother as possible and they are received in regions of extra thickness(8, 9, 10) of the base (2), outside the assembly means (4).
 3. Footwearaccording to claim 2, wherein the bearing member (3) includes recesses(18, 19, 20) for housing said regions of extra thickness when assembledwith the base (2).
 4. Footwear according to claim 3, wherein theassembly means are constituted by a tenon (4) in the form of a maledovetail projecting from the base (2) and a female dovetail (16) formedin the bearing member (3).
 5. Footwear according to claim 4, wherein theregions of extra thickness (8, 9, 10) in which the nuts (11, 12, 13) areembedded are disposed outside the male dovetail (4), while the bearingmember (3) includes corresponding recesses (18, 19, 20) for receivingsaid regions of extra thickness when the two dovetails (4, 16) aremutually engaged and assembled together.